In certain diseased states, the heart lacks sufficient pumping capacity to maintain adequate blood flow to the body's organs and tissues. For example, conditions such as ischemic heart disease and hypertension may leave the heart unable to fill and pump efficiently. This condition, also called congestive heart failure, may lead to serious health complications, including respiratory distress, cardiac asthma, and even death. In fact, congestive heart failure is one of the major causes of death in the Western World.
This inadequacy of the heart can be alleviated by providing a mechanical pump, also referred to as a ventricular assist device (“VAD”), to supplement the pumping action of the heart. VADs may be used to assist the right ventricle, the left ventricle, or both. For example, a VAD may assist the left ventricle by mechanically pumping oxygenated blood from the left ventricle into the aorta.
U.S. Pat. No. 7,976,271 and U.S. Publication No. 2014/0100414 (“the 414 Publication”), the disclosures of which are hereby incorporated by reference herein and copies of which are annexed hereto respectively as exhibits A and B, disclose certain centrifugal blood pumps that can be used as ventricular assist devices. When implanted, these and other implantable pumps, typically have an inlet that communicates with a ventricle of a patient and an outlet that communicates with an aorta via a flexible conduit which is disposed external to the heart. A pumping element typically resides outside of the heart and urges oxygenated blood from the ventricle to the aorta.
U.S. Pat. No. 9,050,418 (“the '418 patent”); U.S. Pat. No. 9,173,984 (“the '984 patent”); U.S. Publication No. 2016/0015878 (“the '878 Publication”), the disclosures of which are hereby incorporated herein by reference and copies of which are annexed hereto as respectively as exhibits C, D and E, disclose certain axial flow blood pumps that can be used as ventricular assist devices. When implanted, these and other implantable pumps, typically have an inlet that communicates with a ventricle of a patient and an outlet that communicates with an aorta via an outflow cannula that extends through the ventricle and into the aorta. A pumping element typically resides within the heart and urges oxygenated blood from the ventricle to the aorta.
When the above-mentioned pumps and other pumps are implanted and in operation, it is desirable to monitor certain parameters to detect abnormal operating conditions and to determine how a pump affects its surrounding environment. For example, flow information can be obtained directly via an ultrasonic flow sensor or indirectly via a pressure sensor. Such information can be used to provide feedback for control of the pump and to detect a blockage or a situation where the pump outpaces a ventricle's blood supply leading to a suction condition. Certain existing VADs are fitted with sensors for detecting some of these parameters. However, despite considerable effort devoted to improvements of such VADs, still further improvement would be desirable.